ABSTRACT
Single-photon emitters (SPEs) are attractive as integrated platforms for quantum applications in technologically mature wide-bandgap semiconductors since their stable operation at room temperature or even at high temperatures. In this study, we systematically studied the temperature dependence of the SPE in AlGaN micropillar by experiment. The photoluminescence (PL) spectrum, PL intensity, radiative lifetime and second-order autocorrelation function measurements are investigated over the temperature range from 303 to 373 K. The point defects of AlGaN show strong zero phonon line in the wavelength range of 800-900 nm and highly antibunched photon emission even up to 373 K. Our study reveals a possible mechanism for linewidth broadening in AlGaN SPE at high temperatures. This indicates a possible key for on-chip integration applications based on this material operating at high temperatures.
ABSTRACT
Point defects in wide bandgap III-nitride semiconductors have been recently reported to be one kind of the most promising near-infrared (NIR) quantum emitters operating at room temperature (RT). But the identification of the point defect species and the energy level structures as well as the transition dynamics remain unclear. Here, the photophysical properties of single-photon emission from point defects in AlGaN films are investigated in detail. According to the first-principles calculations, a three-level model was established to explain the transition dynamics of the quantum emitters. An anti-site nitrogen vacancy complex (VNNGa) was demonstrated to be the most likely origin of the measured emitter since the calculated zero-phonon line (ZPL) and the lifetime of VNNGa in the AlGaN film coincide well with the experimental results. Our results provide new insights into the optical properties and energy level structures of quantum emission from point defects in AlGaN films at RT and establish the foundation for future AlGaN-based on-chip quantum technologies.
ABSTRACT
We report the generation of single negatively charged silicon vacancy (SiV-) color centers by focusing a femtosecond (fs) laser on top of a high-purity diamond coated with a layer of Si nanoball. Under the interaction of a high-intensity fs laser, Si atoms were ionized and implanted into the diamond, accompanied with the creation of vacancies. After annealing at 850°C in vacuum for 1 h, the photoluminescence spectra of bright spots around the created crater presented a typical strong zero-phonon line at around 737 nm of SiV- centers. Bright single SiV- color centers could be observed with a maximum saturating counting rate of 300×103 counts/s. We explain the formation mechanism of SiV- centers in diamond via a Coulomb explosion model. The results demonstrate that fs laser ablation can be utilized as a very promising tool to conveniently fabricate single bright SiV- centers in diamond.
